Houseplants

Question

How do I get those tiny flies or gnats out of the soil in my planters?

Answer 1

Those are probably fungus gnats. See this article for what to do:

https://www.gardeningknowhow.com/plant-problems/pests/insects/fungus-gnats.htm

This technique would probably work if you want to kill off the gnats before planting in the planters:

https://www.gardeningknowhow.com/garden-how-to/projects/how-to-solarize-garden-beds-to-eliminate-garden-pests-in-the-soil.htm

If the soil isn't in the planters yet, you could solarize it inside a black trash bag.